Hydrangea plant named ‘Zebra’

ABSTRACT

A new cultivar of  Hydrangea macrophylla  named ‘Zebra’, a sport of  Hydrangea macrophylla  ‘Schneeball’ that is characterized by its pure white colored inflorescences that are borne on strong, nearly black flower stems.

Genus/species: Hydrangea macrophylla.

Varietal denomination: ‘Zebra’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Hydrangea macrophylla and will be referred to hereafter by its cultivar name, ‘Zebra’. ‘Zebra’ represents a new Bigleaf Hydrangea, a deciduous shrub grown for landscape use and for use as a potted plant.

‘Zebra’ was discovered by the inventor as a naturally occurring branch mutation of Hydrangea macrophylla ‘Schneeball’ (not patented) in June 2003 in De Kwakel, The Netherlands. The inventor produces approximately 10,000 plants of the parent variety ‘Schneeball’ in his nursery annually and discovered one branch on a single plant that was nearly black in coloration; stem cuttings of the mutant branch resulted in the new cultivar, ‘Zebra’.

Asexual reproduction of the new cultivar was first accomplished by softwood stem cuttings in De Kwakel, The Netherlands in July 2003 by the inventor. The characteristics of this cultivar have been determined to be stable and are reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

The following traits have been repeatedly observed and represent the characteristics of the new cultivar. These attributes in combination distinguish ‘Zebra’ as a unique cultivar of Hydrangea macrophylla.

-   -   1. ‘Zebra’ exhibits stems that are nearly black in color.     -   2. ‘Zebra’ exhibits pure white flowers in compound corymbs in         early summer.     -   3. ‘Zebra’ exhibits very strong stems.     -   4. ‘Zebra’ is hardy at least to U.S.D.A. Zone 6.         The only close comparison plant to the new cultivar of Hydrangea         is the parent plant, Hydrangea macrophylla ‘Schneeball’. ‘Zebra’         is similar to ‘Schneeball’ in foliage, flower, and habit         characteristics, however ‘Zebra’ differs in having nearly black         stems whereas ‘Schneeball’ exhibits green stems.

BRIEF DESCRIPTION OF THE DRAWINGS

The photographs in the figures were taken of a one year-old plant of ‘Zebra’ as grown outdoors in a 15 cm container in De Kwakel, The Netherlands.

The photograph on the top of first sheet illustrates a plant of ‘Zebra’ in bloom and the stem color is illustrated.

The photograph on the bottom of the first sheet provides a close-up view of a leaf of ‘Zebra’.

The photograph of the top of the second sheet provides a view of a fully open inflorescence and the photograph on the bottom of the second sheet is a close-up view of the flowers of ‘Zebra’.

The colors in the photographs are as close as possible with the digital photography and printing techniques utilized and the color codes in the detailed botanical description more accurately describe the new Hydrangea.

BOTANICAL DESCRIPTION OF THE PLANT

The following is a detailed description of one year-old plants of the new cultivar as grown in 15 cm containers under ambient light, outdoors in De Kwakel, The Netherlands. Phenotypic differences may be observed with variations in environmental, climatic, and cultural conditions. The color determination is in accordance with the 2001 R.H.S. Colour Chart of The Royal Horticultural Society, London, England, except where general color terms of ordinary dictionary significance are used.

-   Botanical classification: ‘Zebra’ is a cultivar of Hydrangea     macrophylla. -   Commercial classification: Bigleaf hydrangea, Hortensia type. -   Parentage: Naturally occurring branch sport of Hydrangea     machrophylla ‘Scheeball’. -   General description:     -   -   Blooming period.—Early summer blooming.         -   Plant habit.—Broadly upright, deciduous shrub.         -   Height and spread.—Reaches about 45 cm in height and 34.5 cm             width when mature.         -   Cold hardiness.—At least to U.S.D.A. Zone 6, colder zones             have not been tested.         -   Heat tolerance.—Known to tolerate temperatures of at least             32° C.         -   Culture.—Grows best in most but well-drained, humus-rich             soil in full sun or partial shade with protection from high             winds.         -   Diseases resistance.—No susceptibility or resistance             diseases known to effect H. macrophylla has been observed.         -   Root description.—Fine. -   Growth and propagation:     -   -   Propagation.—Softwood stem cuttings.         -   Time required for root development.—About 3 weeks to fully             develop in a liner as grown under greenhouse conditions at             an average temperature of 20° C.         -   Time required to produce a salable crop.—About 12 months             from propagation to a flowering plant in a 15 cm container.         -   Growth rate and vigor.—Moderate, growth rate is about 15 cm             per month in spring. -   Stem description:     -   -   Stem shape.—Round, solid.         -   Stem strength.—Strong.         -   Stem color.—N186C to 200A but darker.         -   Stem size.—Average of 25 cm (to base of inflorescence),             average of 6 mm in width.         -   Stem surface.—Glabrous, glossy, sparsely covered with             lenticels; about 8 per square cm, about 2.5 mm in length and             0.5 mm in width and 152A to 152B in color.         -   Internode length.—Average of 7.1 cm.         -   Branching.—A single dormant stem will produce an average of             4 lateral branches, sublateral branching is determined by             pinching; 2 stems develop per pinched node. -   Foliage description:     -   -   Leaf shape.—Ovate to broadly ovate.         -   Leaf arrangement.—Opposite.         -   Leaf division.—Simple.         -   Leaf number.—Average of 8 (4 pairs) per lateral branch.         -   Leaf base.—Obtuse.         -   Leaf apex.—Apiculate.         -   Leaf margins.—Serrated.         -   Leaf venation.—Penninerved, recessed on upper surface, color             144A to 144B on upper surface and 145 a to 145B on lower             surface.         -   Leaf size.—Average of 9.1 cm in length and 7.3 cm in width.         -   Leaf attachment.—Petiolate.         -   Leaf surface.—Glabrous on upper and lower surface, slightly             glossy on upper surface.         -   Leaf color.—Young foliage upper surface; 143A, young foliage             lower surface; 143B to 143C, mature foliage upper surface;             137A to 137B, mature foliage lower surface; 137B to 137C to             143A.         -   Petioles.—Average of 1.7 cm in length and 3 mm in width,             144A to 144B in color. -   Inflorescence description:     -   -   Inflorescence type.—Terminal compound globose corymb of             rotate shaped flowers, about 77% of the flowers are sterile.         -   Lastingness of inflorescence.—Persistent but color is             retained for about 4 weeks.         -   Inflorescence number.—One per lateral or sublateral stem if             pinched.         -   Inflorescence size.—Average of 8.8 cm in height and 14.2 cm             in diameter.         -   Flower number.—Numerous, average of 150 sterile flowers and             45 fertile flowers per inflorescence.         -   Flower durability to stress.—High.         -   Flower fragrance.—Faint.         -   Time required to develop an inflorescence.—Approximately 9             weeks after growth emerges when container grown.         -   Flower aspect.—Upright to outward.         -   Flower size.—Sterile flowers; average of 4.1 cm in diameter             and 1.1 cm in depth, fertile flowers; average of 6 mm in             diameter and 6 mm in depth.         -   Flower buds.—Average of 3.5 mm in length and 4 mm in width             prior to opening, flattened globular in shape, 155D in             color, flowers open in about 3 days from mature bud.         -   Peduncles.—Strong, average of 3.7 cm in length and 2.5 mm in             width, held at about a 50° angle from vertical, 187A to 187B             in color, surface is glabrous and shiny.         -   Pedicels.—Moderate strength, average of 3.5 cm in length on             the sterile flowers and 1.9 cm in length on fertile flowers,             4 mm in width, held at about a 15 to 30° angle from             vertical, 185B to 187C in color, surface is glabrous and             shiny.         -   Calyx.—Campanulate in form, average of 2 cm in length and 4             mm in diameter.         -   Petals.—Average of 5, present on fertile flowers only,             rotate in arrangement, ovate in shape, entire margin, acute             apex, cuneate base, average of 1.5 mm in length and 1 mm in             width, surface is glabrous and dull on both surfaces, color             of upper and lower surface (opening and mature flowers) is             155A.         -   Sepals.—Average of 4 for sterile flowers, average of 5 for             fertile flowers, un-fused, rotate in arrangement, glabrous             and dull surface (both surfaces), orbicular to reniform in             shape on sterile flowers, ovate in shape on fertile flowers,             margin is entire on fertile flowers and crenate to bluntly             serrate on sterile flowers, apex is rounded on sterile             flowers and acute on fertile flowers, size on sterile             flowers; average of 2.3 cm in length and 2.8 cm in width,             size on fertile flowers; average of 3 mm in length and 2 mm             in width, color remains the same through development on             fertile and sterile flowers and on both sepal surfaces; pure             white (whiter than any color on The R.H.S. colour chart but             closest to 155A). -   Reproductive organs: (fertile flowers):     -   -   Stamens.—Average of 9, anther is short oblong in shape,             about 1 mm in length and 158D in color, filament is an             average of 2.5 mm in length and whiter R.H.S. Color codes in             color, pollen is low in quantity and 158D in color.         -   Pistils.—Average of 3, average of 1.2 mm in length, stigma             is club-shaped and 155C in color, style is an average of 0.7             mm in length and 155C in color, ovary is inferior and 155C             in color.         -   Fruit and seed.—Has not been observed under the conditions             tested to date. 

1. A new and distinct cultivar of Hydrangea plant named ‘Zebra’ substantially as herein illustrated and described. 